The objective of this project is to identify agents suitable for short term clinical trials. The materials screened belong to two general categories, cationic antiseptics and antibiotics. Screening is conducted both in vitro and in animals. The in vitro phase screens on such parameters as adsorption, minimal inhibitory concentration, contact angle and modification of enamel dissolution rate. The animal phase measures caries control and plaque control and also monitors untoward effects such as acute toxicity and staining.